JP2022002203A - Luminous flux control member, light emitting device, surface light source device, and display device - Google Patents

Abstract

To provide a luminous flux control member that can more appropriately distribute light from a plurality of light emitting elements while improving handleability at the time of mounting by arranging the luminous flux control member on the plurality of light emitting elements.SOLUTION: A luminous flux control member 700 comprises a plurality of incidence units 310 for making light emitted from a plurality of light emitting elements incident thereon, and an emitting unit arranged between the plurality of incidence units 310, and for emitting the light incident on the plurality of incidence units 310 while guiding it. The plurality of incidence units 310 each comprises an incidence surface, and a first reflection surface 321 for reflecting the light incident on the incidence surface, in a direction along a board. The emitting unit comprises: a second emitting surface arranged so as to be opposed to the board, and for reflecting the light from the incidence units 310; a first emitting surface arranged so as to be opposed to the second emitting surface, and for emitting the light from incidence units 310; and an emission promotion part 340 for promoting the emission of the light traveling between the second emitting surface and the first emitting surface, from the first emitting surface.SELECTED DRAWING: Figure 18

Description

The present invention relates to a light flux control member that controls the distribution of light emitted from a light emitting element, a light emitting device having the light beam control member, a surface light source device having the light emitting device, and a display device having the surface light source device.

In a transmissive image display device such as a liquid crystal display device, a direct type surface light source device having a plurality of light emitting elements as a light source has been used in recent years. In addition, a large number of light emitting elements may be arranged to irradiate light over a wide range.

Patent Document 1 discloses a luminous flux control member (microarray lens) suitable for being arranged on a large number of light emitting elements. In this microarray lens, a large number of lenses are connected by a support plate, and one microarray lens is arranged on a large number of light emitting elements (mini LEDs) arranged on a substrate. By doing so, it is not necessary to arrange individual lenses on the individual light emitting elements, the handling property at the time of mounting is improved, and the mounting becomes easy.

Chinese Patent Application Publication No. 110208984

Although the above-mentioned luminous flux control member (microarray lens) has good handleability at the time of mounting, the luminous flux control member may become thick when trying to distribute the light from the light emitting element as desired. .. As a result, the surface light source device may also become thick.

The present invention has been made in view of the above circumstances, and the light from the plurality of light emitting elements can be obtained while improving the handleability at the time of mounting by arranging one light flux control member on the plurality of light emitting elements. It is an object of the present invention to provide a luminous flux control member capable of appropriately distributing light.

Another object of the present invention is to provide a light emitting device, a surface light source device, and a display device having the above-mentioned luminous flux control member.

The light beam control member of the present invention is a light beam control member for controlling the light distribution of light emitted from a plurality of light emitting elements arranged on a substrate, and the light emitted from the plurality of light emitting elements is respectively. A plurality of incident units for making incident light, and a plurality of emitting units arranged between the plurality of incident unit in the direction along the substrate and emitting light incident on the plurality of incident units while guiding light. Each of the plurality of incident units is arranged on the back side of the light beam control member, and the incident surface on which the light emitted from the light emitting element is incident and the incident surface on the front side of the light beam control member are sandwiched between the incident surface and the incident surface. The plurality of emitting units include a first reflecting surface which is arranged at a position facing the light emitting element and reflects light incident on the incident surface laterally so as to be away from the optical axis of the light emitting element. A second emission surface, which is arranged on the back side of the light beam control member and reflects a part of the light from the incident unit to emit the other part, and a second emission surface on the front side of the light beam control member. A first emission surface that reflects a part of the light from the incident unit and emits the other part, and at least one of the first emission surface and the second emission surface. It has an emission promoting unit for promoting the emission of light traveling between the first emission surface and the second emission surface, and the emission promoting unit has a traveling direction of the reached light. Includes a ray direction change part including an inclined surface for changing the light.

The light emitting device of the present invention has a plurality of light emitting elements arranged on a substrate, and the above-mentioned luminous flux control member arranged on the plurality of light emitting elements.

The surface light source device of the present invention has a plurality of the above-mentioned light emitting devices and a light diffusing plate that diffuses and transmits the light emitted from the plurality of light emitting devices.

The display device of the present invention includes the above-mentioned surface light source device and a display member irradiated with light emitted from the surface light source device.

According to the present invention, it is possible to more appropriately distribute the light from the plurality of light emitting elements while improving the handleability at the time of mounting by arranging one light flux control member on the plurality of light emitting elements. A luminous flux control member can be provided.

Further, according to the present invention, it is possible to provide a light emitting device, a surface light source device, and a display device having the above-mentioned luminous flux control member.

1A and 1B are diagrams showing the configuration of the surface light source device according to the first embodiment. 2A to 2C are views showing the configuration of the surface light source device according to the first embodiment. FIG. 3 is a partially enlarged view of FIG. 2B. 4A to 4C are views showing the configuration of the light flux control member according to the first embodiment. 5A to 5D are cross-sectional views of the light flux control member according to the first embodiment. 6A and 6B are views showing a modified example of the emission promoting portion. 7A and 7B are views showing a modified example of the emission promoting portion. 8A and 8B are views showing a modified example of the emission promoting portion. 9A and 9B are views showing a modified example of the emission promoting portion. 10A and 10B are optical path diagrams of the light emitting device according to the first embodiment. 11A to 11C show the illuminance distribution of the light emitting device according to the first embodiment. 12A and 12B show the illuminance distribution of the light emitting device according to the first embodiment. 13A to 13C show a modification of the luminous flux control member according to the first embodiment. 14A to 14C show a modification of the luminous flux control member according to the first embodiment. 15A to 15C are views showing the configuration of the light flux control member according to the second embodiment. 16A to 16C are cross-sectional views of the light flux control member according to the second embodiment. 17A to 17C show the illuminance distribution of the light emitting device or other light emitting device according to the second embodiment. 18A and 18B are views showing the configuration of the luminous flux control member according to the third embodiment. 19A to 19E are views showing the configuration of the light flux control member according to the third embodiment. 20A to 20C are diagrams for explaining that the direction of the light ray is changed by the light ray direction changing portion. 21A to 21F show an example of a ray direction changing portion. FIG. 22 is a diagram showing the configuration of the luminous flux control member according to the third embodiment. 23A and 23B show the illuminance distribution of the light emitting device according to the third embodiment. 24A to 24F are views showing the configuration of the light flux control member according to the fourth embodiment. FIG. 25 shows the illuminance distribution of the light emitting device according to the fourth embodiment. 26A to 26F are views showing the configuration of the luminous flux control member according to the fifth embodiment. FIG. 27 shows the illuminance distribution of the light emitting device according to the fifth embodiment. FIG. 28 is a diagram for explaining how to mount the luminous flux control member.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the following description, as a typical example of the surface light source device according to the present invention, a surface light source device suitable for a backlight of a liquid crystal display device or the like will be described. These surface light source devices can be used as a display device 100'by combining with a display member 102 (for example, a liquid crystal panel) irradiated with light from the surface light source device (see FIG. 1B).

[Embodiment 1]
(Structure of surface light source device and light emitting device)
1A and 1B are views showing the configuration of the surface light source device 100 according to the first embodiment of the present invention. 1A is a plan view, and FIG. 1B is a front view. 2A is a cross-sectional view taken along the line AA shown in FIG. 1B, FIG. 2B is a cross-sectional view taken along the line BB shown in FIG. 1A, and FIG. 2C shows a light emitting element 220 and a luminous flux control member 300. It is a partially enlarged plan view which shows the positional relationship with. FIG. 3 is a partially enlarged cross-sectional view of a part of FIG. 2B.

As shown in FIGS. 1A to 1, the surface light source device 100 according to the present embodiment includes a housing 110, a plurality of light emitting devices 200, and a light diffusing plate 120. The plurality of light emitting devices 200 are arranged in a grid pattern (matrix shape) on the bottom plate 112 of the housing 110. The inner surface of the bottom plate 112 functions as a diffuse reflection surface. Further, the top plate 114 of the housing 110 is provided with an opening. The light diffusing plate 120 is arranged so as to close this opening, and functions as a light emitting surface. The size of the light emitting surface is not particularly limited, but is, for example, about 400 mm × about 700 mm.

As shown in FIG. 3, the light emitting device 200 is fixed on the substrate 210. The substrate 210 is fixed at a predetermined position on the bottom plate 112 of the housing 110. The light emitting device 200 includes a light emitting element 220 and a luminous flux control member 300.

The light emitting element 220 is a light source of the surface light source device 100 and is mounted on the substrate 210. The light emitting element 220 is a light emitting diode (LED) such as a white light emitting diode. The type of the light emitting element 220 is not particularly limited, but a light emitting element 220 (for example, a COB type light emitting diode) that emits light from the top surface and side surfaces is suitable for the light emitting device 200 according to the embodiment of the present invention. Used for. The size of the light emitting element 220 is not particularly limited, but is preferably 0.1 mm to 0.6 mm. Further, it is more preferably 0.1 mm to 0.3 mm. In the present invention, it is possible to obtain an optical control member which can distribute light more appropriately and has less color unevenness by using a smaller LED.

The luminous flux control member 300 is an optical member that controls the light distribution of the light emitted from the light emitting element 220, and is fixed on the substrate 210. As will be described later, the luminous flux control member 300 has a plurality of incident units 310, and in the luminous flux control member 300, the central axis CA of each incident unit 310 (incident surface 320) is the optical axis LA of each light emitting element 220. It is arranged on a plurality of light emitting elements 220 so as to match. In the luminous flux control member 300 according to the present embodiment, the incident unit 310 (incident surface 320 and the first reflecting surface 321) of the luminous flux control member 300 is rotationally symmetric. The axis of rotation of the incident unit 310 is referred to as "incident unit 310, incident surface 320, or central axis CA of first reflecting surface 321". Further, the "optical axis LA of the light emitting element 220" means a light ray at the center of a three-dimensional emitted light flux from the light emitting element 220. A gap may or may not be formed between the substrate 210 on which the light emitting element 220 is mounted and the back surface of the luminous flux control member 300 to release the heat generated from the light emitting element 220 to the outside. May be good.

The luminous flux control member 300 is integrally molded. The material of the luminous flux control member 300 is not particularly limited as long as it is a material capable of passing light of a desired wavelength. For example, the material of the luminous flux control member 300 is a light-transmitting resin such as polymethyl methacrylate (PMMA), polycarbonate (PC), or epoxy resin (EP), or glass.

The surface light source device 100 according to the present embodiment has a main feature in the configuration of the luminous flux control member 300. Therefore, the luminous flux control member 300 will be described in detail separately.

The light diffusing plate 120 is a plate-shaped member having light diffusing properties, and transmits light emitted from the light emitting device 200 while diffusing it. Usually, the light diffusing plate 120 has almost the same size as a display member such as a liquid crystal panel. For example, the light diffusing plate 120 is formed of a light transmissive resin such as polymethyl methacrylate (PMMA), polycarbonate (PC), polystyrene (PS), and styrene / methyl methacrylate copolymer resin (MS). In order to impart light diffusivity, fine irregularities are formed on the surface of the light diffusing plate 120, or light diffusing elements such as beads are dispersed inside the light diffusing plate 120.

In the surface light source device 100 according to the present embodiment, the light emitted from each light emitting element 220 is spread by the luminous flux control member 300 so as to illuminate a wide range of the light diffusing plate 120. The light emitted from each luminous flux control member 300 is further diffused by the light diffusing plate 120. As a result, the surface light source device 100 according to the present embodiment can uniformly illuminate the surface-shaped display member (for example, a liquid crystal panel).

As shown in FIGS. 2A and 2C, in the present embodiment, the plurality of light emitting elements 220 and the plurality of light emitting devices 200 are all arranged in a grid pattern and separated from each other. The distance L1 between the adjacent light emitting devices 200 may be smaller than half of the center-to-center distance L2 of the plurality of light emitting elements 220. Here, the "center-to-center distance L2 of the plurality of light-emitting elements 220" means the center-to-center distance of two light-emitting elements 220 belonging to different light-emitting devices 200. By doing so, the light is guided more widely by the luminous flux control member 300, and it is possible to prevent the space between the light emitting devices 200 from becoming dark.

It is also important that there is a gap between the adjacent light emitting devices 200 and that the light emitting devices 200 are arranged so as not to be in contact with each other. If the light is not arranged with a gap, the light emitted from the end portion may be incident on the end portion of the adjacent light flux control member or reflected at the end portion, which adversely affects the light emission quality on the diffuser plate.

(Structure of luminous flux control member)
4A is a plan view of the luminous flux control member 300 according to the first embodiment, FIG. 4B is a bottom view of the luminous flux control member 300, and FIG. 4C is a perspective view of the luminous flux control member 300. 5A is a sectional view taken along line AA of FIG. 4A, FIG. 5B is a sectional view taken along line BB of FIG. 4A, FIG. 5C is a sectional view taken along line CC of FIG. 4A, and FIG. 5D. Is a partially enlarged view of FIG. 5A. Hereinafter, the configuration of the luminous flux control member 300 according to the first embodiment will be described.

The luminous flux control member 300 according to the present embodiment is a luminous flux control member 300 for controlling the orientation of light emitted from a plurality of light emitting elements 220 arranged on the substrate 210, and includes a plurality of incident units 310. , And an emission unit 330. The plurality of incident units 310 are arranged in a grid pattern corresponding to the arrangement of the light emitting elements 220. The emitting unit 330 is arranged between the plurality of incident units 310 in the direction along the substrate 210.

Each of the plurality of incident units 310 incidents the light emitted from the light emitting element 220. The incident unit 310 has an incident surface 320 for incident light emitted from the light emitting element 220 and a first reflecting surface 321 for reflecting the light incident on the incident surface 320 toward the emitting unit 330.

The incident surface 320 is an inner surface of a recess arranged on the back side of the luminous flux control member 300 and formed at a position facing the light emitting element 220. The incident surface 320 causes most of the light emitted from the light emitting element 220 to enter the inside of the luminous flux control member 300 while controlling the traveling direction thereof. The incident surface 320 intersects the optical axis LA of the light emitting element 220 and is rotationally symmetric (circular symmetry) with respect to the optical axis LA. The shape of the incident surface 320 is not particularly limited, and the light incident on the incident surface 320 is set so as to be directed to the first reflecting surface 321 and the first emitting surface 333. In the present embodiment, the incident surface 320 gradually increases in distance from the substrate 210 as it moves away from the optical axis LA of the light emitting element 220, and then gradually increases in distance from the substrate 210 as it moves away from the optical axis LA of the light emitting element 220. The shape is such that it becomes shorter.

The first reflecting surface 321 is arranged at a position facing the light emitting element 220 on the front side of the light flux control member 300 with the incident surface 320 interposed therebetween so that the light incident on the incident surface 320 is separated from the optical axis LA of the light emitting element 220. Reflect in the lateral direction. Here, the lateral direction does not mean the outer edge direction of the light flux control member, but means toward the outside in the radial direction of 360 ° about the optical axis.

By doing so, the first reflecting surface 321 suppresses the light incident on the incident surface 320 from escaping upward to prevent a bright portion from being generated directly above the light emitting element 220, and between the light emitting elements 220. It also guides light to prevent dark areas from being generated between the light emitting elements 220. The shape of the first reflecting surface 321 is not particularly limited as long as the light incident from the incident surface 320 can be reflected laterally. The first reflecting surface 321 is, for example, rotationally symmetric (circularly symmetric) with respect to the optical axis LA of the light emitting element 220, and faces the front side (away from the substrate 210) as the distance from the optical axis LA of the light emitting element 220 increases. It may be configured in.

The generatrix from the central portion to the outer peripheral portion of the rotational symmetry is a curved line or a straight line inclined with respect to the optical axis of the light emitting element 220. The first reflecting surface 321 is a concave surface in a state where the generatrix is rotated by 360 ° with the central axis CA of the incident surface 320 as a rotation axis. In this embodiment, the generatrix is a straight line.

As shown in FIG. 5D, the first reflective surface 321 may have a plurality of ridges 390 arranged so as to connect a central portion thereof and an outer edge thereof. Each ridge 390 is a ridge that is a boundary line between a first sloping surface 391, a second sloping surface 392 arranged in pairs with the first sloping surface 391, and a boundary line between the first sloping surface 391 and the second sloping surface 392. It has a ridgeline 393. The plurality of ridges 390 are arranged so that a valley is formed between the ridges 390 and the adjacent ridges 390.

Since the first reflecting surface 321 has such a ridge 390, it is possible to further suppress the light incident on the incident surface 320 from being reflected more and the light from passing upward.

In the present invention, the incident surface 320 and the first reflecting surface 321 are the inner surfaces of the recesses, respectively, and when viewed in a plan view, the first reflecting surface is relative to the area of the opening edge of the recess constituting the incident surface. The area of the opening edge of the concave portion constituting the above is preferably 0.5 times to 2.0 times. Further, it is more preferably 0.5 times to 1.5 times, and particularly preferably 0.5 times to 1.3 times. As described above, the size of the first reflecting surface with respect to the incident surface is smaller than that of the conventional total reflection lens. This is because the present invention is designed so that the light emitted from the center of the light emitting element and incident on the incident surface reaches not only the first reflecting surface but also the first emitting surface. ..

The emission unit 330 emits light incident on by the plurality of incident units 310 while guiding the light. In the present embodiment, assuming that the four incident units 310 are arranged at each corner of the virtual quadrangle, the luminous flux control member 300 is arranged along each side at a position corresponding to the four sides of the virtual quadrangle. It has four emission units 330 arranged and one emission unit 330 arranged so as to be surrounded by a virtual quadrangle. As shown in FIGS. 5A to 5C, each emission unit 330 is arranged on the back side of the luminous flux control member 300 and has a second emission surface 332 that reflects light from the first reflection surface 321 of the incident unit 310. Further, the emission unit 330 is arranged on the front side of the luminous flux control member 300 so as to face the second emission surface 332, and the first emission surface that reflects a part of the light from the incident unit 310 and emits the other part. It has 333.

Further, the emission unit 330 has an emission promotion unit 340 for promoting the emission of light traveling between the second emission surface 332 and the first emission surface 333. The emission promotion unit 340 is arranged on at least one of the second emission surface 332 and the first emission surface 333.

In the present embodiment, as shown in FIGS. 5A to 5C, the emission promotion unit 340 is formed on the first emission surface 333, and the distance between the first emission surface 333 and the second emission surface 332 is incident. The farther away from the unit 310, the smaller it becomes. With such a configuration, the light guided from the incident unit 310 is more likely to be emitted from the first exit surface 333 as the distance from the incident unit 310 increases.

The shape of the first exit surface 333 is not particularly limited. In the present embodiment, the four first exit surfaces 333 arranged at positions corresponding to the four sides of the virtual quadrangle have a curvature in the direction along the side of the virtual quadrangle, and the direction perpendicular to this side. Is a concave surface having no curvature (see FIGS. 5A to 5C). On the other hand, the first exit surface 333 arranged so as to be surrounded by the virtual quadrangle is a concave surface formed by a part of the upper bottom and the side surface of the truncated cone arranged upside down (FIGS. 5B and 5C). reference).

The configuration of the emission promotion unit 340 is not limited to the above example as long as the above function can be exhibited. For example, the emission promotion unit 340 is at least one selected from the group consisting of a concave surface, a rough surface, a Fresnel surface, a groove, and a through hole arranged on at least one of the second emission surface 332 and the first emission surface 333. It may be one or more.

When the emission promoting portion 340 is a concave surface formed on the second emission surface 332 or the first emission surface 333, the distance between the second emission surface 332 and the first emission surface 333 becomes smaller as the distance from the incident unit 310 increases. Light traveling between the two emission surfaces 332 and the first emission surface 333 is likely to be emitted from the first emission surface 333. When the emission promoting portion 340 is a rough surface formed on the second emission surface 332, the light traveling between the second emission surface 332 and the first emission surface 333 is diffusely reflected on the rough surface instead of specular reflection. It becomes easy to be emitted from the first emission surface 333. When the emission promoting portion 340 is a rough surface formed on the first emission surface 333, the light traveling between the second emission surface 332 and the first emission surface 333 is diffused and transmitted on the rough surface instead of specular reflection. , It becomes easy to be emitted from the first emission surface 333. When the emission promoting portion 340 is a Fresnel surface or a groove formed on the second emission surface 332, the light traveling between the second emission surface 332 and the first emission surface 333 is the surface forming the Fresnel surface or the groove. Since the light is reflected toward the first emission surface 333 so that the incident angle on the first emission surface 333 becomes smaller, the light is easily emitted from the first emission surface 333. When the emission promoting portion 340 is a Fresnel surface or a groove formed on the first emission surface 333, the light traveling between the second emission surface 332 and the first emission surface 333 constitutes the Fresnel surface or the Fresnel surface. Since it is emitted on the surface, it is likely to be emitted from the first emission surface 333. When the emission promoting portion 340 is a through hole opened in the second emission surface 332 and the first emission surface 333, the light traveling between the second emission surface 332 and the first emission surface 333 constitutes the through hole. Since it is emitted on the surface, it is likely to be emitted from the first emission surface 333.

6A to 9B are views of the luminous flux control member 300 for showing a modification of the emission promoting unit 340. In these figures, the luminous flux control member 300 in which the first reflecting surface 321 of the incident unit 310 does not have the ridges 390 is shown.

6A and 6B are views of the luminous flux control member 300 in which the emission promoting portion 340 is formed on the second emission surface 332 and is two concave surfaces 10 having a substantially triangular cross-sectional view. 6A is a plan view of the luminous flux control member 300, and FIG. 6B is a cross-sectional view taken along the line BB of FIG. 6A.

7A and 7B are views of the luminous flux control member 300 in which the emission promoting portion 340 is formed on the second emission surface 332 and the cross-sectional view is two concave surfaces 10 having a substantially arc shape. 7A is a plan view of the luminous flux control member 300, and FIG. 7B is a cross-sectional view taken along the line BB of FIG. 7A.

8A and 8B are views of the luminous flux control member 300 in which the emission promoting portion 340 is formed on the second emission surface 332 and the cross-sectional view is two concave surfaces 10 having a substantially trapezoidal shape. 8A is a plan view of the luminous flux control member 300, and FIG. 8B is a cross-sectional view taken along the line BB of FIG. 8A.

9A and 9B are views of the luminous flux control member 300 in which the emission promoting portion 340 is formed on the second emission surface 332 and the cross-sectional view is one concave surface 10 having a substantially trapezoidal shape. 9A is a plan view of the luminous flux control member 300, and FIG. 9B is a cross-sectional view taken along the line BB of FIG. 9A.

(Light distribution)
FIG. 10A is an optical path diagram of the light emitting device 200. As shown in FIG. 10A, the light emitted from the light emitting element 220 is incident on the luminous flux control member 300 at the incident surface 320. A part of the light incident on the incident surface 320 is directly directed to the emitting unit 330, and the other part is reflected by the first reflecting surface 321 and directed to the emitting unit 330. The light that has reached the emission unit 330 is repeatedly reflected between the second emission surface 332 and the first emission surface 333, and is guided through the emission unit 330. At this time, a part of the light that has reached the first emission surface 333 is emitted from the first emission surface 333 without being reflected.

In this way, the light that has reached the emission unit 330 travels between the second emission surface 332 and the first emission surface 333 of the emission unit 330, and is gradually emitted from the first emission surface 333. Here, the emission unit 330 has an emission promotion unit 340 in which the distance between the second emission surface 332 and the first emission surface 333 becomes smaller as the distance from the incident unit 310 increases. As a result, the farther away from the incident unit 310, the easier it is for light traveling between the second emission surface 332 and the first emission surface 333 to be emitted from the first emission surface 333.

FIG. 10B shows the light distribution at the end of the luminous flux control member 300. As shown in FIG. 10B, the cross-sectional shape of the end portion of the luminous flux control member 300 may be rectangular or chamfered. That is, the outer edge on the front side of the luminous flux control member 300 may be chamfered. Examples of the chamfered shape include R chamfering, C chamfering (inclined surface), and the like. When the cross-sectional shape of the end portion of the luminous flux control member 300 is chamfered, it is possible to irradiate a wide area of the diffuser plates located between the light emitting devices, and the space between the light emitting devices 200 having a gap becomes dark. Can be prevented.

(Illuminance distribution)
11A to 11C show the illuminance distribution of the surface light source device 100 according to the present embodiment. Here, the illuminance distribution on the light diffusing plate 120 when only the 1 to 4 light emitting elements 220 included in one light emitting device 200 are turned on in the surface light source device 100 is shown.

11A shows the illuminance distribution when all four light emitting elements 220 are turned on, FIG. 11B shows the illuminance distribution when the lower two of the four light emitting elements 220 are turned on, and FIG. 11C shows the illuminance distribution. The illuminance distribution when the lower one of the four light emitting elements 220 is turned on is shown. Further, in these figures, the lower graph shows the lateral illuminance distribution between the upper two light emitting elements 220 and the lower two light emitting elements 220, and the right graph shows the two right ones. The illuminance distribution in the vertical direction passing through the light emitting center of the light emitting element 220 of the above is shown.

From these results, it can be seen that the luminous flux control member 300 according to the present embodiment spreads the light emitted from each light emitting element 220 and illuminates the region corresponding to each light emitting element 220 substantially uniformly. On the other hand, it can also be seen that the luminous flux control member 300 according to the present embodiment reaches the region corresponding to the light emitting element 220 without excessively mixing the light from each light emitting element 220.

As described above, according to the luminous flux control member 300 according to the present embodiment, it is possible to prevent the light from spreading too much while spreading the light from the light emitting element 220 to some extent, and a predetermined region associated with each light emitting element 220. It is easy to increase only the illuminance of (local dimming). This is because the luminous flux control member 300 has an emission promoting unit in which the distance between the second emission surface 332 and the first emission surface 333 becomes smaller as the distance from the incident unit increases, and the light emitted from a certain light emitting element 220 is emitted from the emission unit. This is because it is difficult to reach another light emitting element 220 (adjacent light emitting element 220) through 330.

FIG. 12A shows a state in which two light emitting devices 200 are arranged side by side. FIG. 12B shows the illuminance distribution when the four light emitting elements 220 of the light emitting device 200 on the left side are turned on in a state where the two light emitting devices 200 are arranged side by side as shown in FIG. 12A. The graph at the bottom of FIG. 12B shows the lateral illuminance distribution through the light emitting centers of the four light emitting elements 220 above the two light emitting devices 200, and the graph on the right is the right 2 of the light emitting device 200 on the left. The illuminance distribution in the vertical direction passing through the light emitting center of the light emitting elements 220 is shown.

As can be seen from this result, the light from the left light emitting device 200 spreads only on the left light emitting device 200. That is, according to the light emitting device 200 according to the present embodiment, the light does not spread to the adjacent light emitting device 200.

(effect)
According to the luminous flux control member 300 of the present embodiment, even when the distance between the substrate 210 and the light diffusing plate 120 is narrow, it is appropriate while suppressing excessive spread of light from a plurality of light emitting elements 220. It can be expanded within the range. Therefore, the present invention is effective for local dimming. Further, according to the present invention, since the light from the plurality of light emitting elements 220 can be controlled by one luminous flux control member 300, the light flux control member 300 can be easily mounted.

[Modification example]
Although the light flux control member having the four incident units 310 arranged on the four light emitting elements 220 has been described above, the light flux control member is not limited to this. The luminous flux control member of the present invention is not particularly limited as long as it is used for a plurality of light emitting elements 220.

13A, B, and C show a plan view, a bottom view, and a perspective view of a light flux control member 400 having six incident units 310 arranged on the six light emitting elements 220, respectively. 14A, B, and C show a plan view, a bottom view, and a perspective view of a light flux control member 500 having eight incident units 310 arranged on eight light emitting elements 220, respectively. The luminous flux control members 400 and 500 have an incident unit 310 and an emission unit 330, respectively, like the luminous flux control member 300.

(effect)
The luminous flux control members 400 and 500 according to the modified example have the same effect as the luminous flux control member 300. Further, since the luminous flux control members 400 and 500 are arranged on more light emitting elements 220, the mounting becomes easier than the luminous flux control member 300.

As described above, in the present invention, the shape of the optical control member is not particularly limited, and examples thereof include a square shape, a rectangular shape, a circular shape, and an octagonal shape. For example, it is possible to control the light by forming a notch between the incident units.

Further, in the present invention, it is preferable that the optical control member has legs. By having the legs, it is possible to prevent heat from being trapped by the light emitting element and to reduce the optical influence of the adhesive when adhering to the substrate.

[Embodiment 2]
The surface light source device according to the second embodiment differs from the surface light source device 100 according to the first embodiment only in the configuration of the luminous flux control member 600. Therefore, in the second embodiment, only the configuration of the luminous flux control member 600 will be described. Further, the same components as those of the luminous flux control member 300 according to the first embodiment are designated by the same reference numerals, and the description thereof will be omitted.

(Structure of luminous flux control member)
15A to 15D show the luminous flux control member 600 according to the second embodiment. 15A is a plan view of the luminous flux control member 600 according to the second embodiment, FIG. 15B is a bottom view of the luminous flux control member 600, and FIG. 15C is a perspective view of the luminous flux control member 600 as viewed from the front side. FIG. 15D is a perspective view seen from the back side of the luminous flux control member 600.

16A is a side view of the luminous flux control member 600, FIG. 16B is a cross-sectional view taken along the line BB of FIG. 15A, and FIG. 16C is a cross-sectional view taken along the line CC of FIG. 15A. Hereinafter, the configuration of the luminous flux control member 600 according to the second embodiment will be described.

The luminous flux control member 600 according to the present embodiment is a luminous flux control member 600 for controlling the orientation of light emitted from a plurality of light emitting elements 220 arranged on the substrate 210, and includes a plurality of incident units 610. , And an emission unit 630. The plurality of incident units 610 are arranged in a grid pattern corresponding to the arrangement of the light emitting elements 220. The emitting unit 630 is arranged between the plurality of incident units 610 in the direction along the substrate 210.

Each of the plurality of incident units 610 incidents the light emitted from the light emitting element 220. The incident unit 610 has an incident surface 620 for incident light emitted from the light emitting element 220 and a first reflecting surface 621 for reflecting the light incident on the incident surface 320 toward the emitting unit 330.

The incident surface 620 is an inner surface of a recess arranged on the back side of the luminous flux control member 600 and formed at a position facing the light emitting element 220. The incident surface 620 causes most of the light emitted from the light emitting element 220 to enter the inside of the luminous flux control member 300 while controlling the traveling direction thereof. The incident surface 620 intersects the optical axis LA of the light emitting element 220 and is rotationally symmetric (circular symmetry) with respect to the optical axis LA. In the present embodiment, the recess constituting the incident surface 620 has a shape in which a small deep recess is arranged in the center of a large shallow recess. The small recess in the center has a shape in which the distance from the substrate 210 gradually decreases as the distance from the optical axis LA of the light emitting element 220 gradually decreases, and a part of the incident surface 620 formed by the small recess is from the light emitting element 220. The light from the light emitting element 220 is controlled so that the light emitted at a small angle with respect to the optical axis LA directs to a region other than the central portion of the first reflecting surface 621. The large recess located around the small recess has a shape in which the distance from the substrate 210 is substantially constant for a while even if it is separated from the optical axis LA of the light emitting element 220, and then gradually shortens. A part of the incident surface 620 is controlled to control the light emitted from the light emitting element 220 so that the light emitted from the light emitting element 220 at a large angle with respect to the optical axis LA is directed to the first emission surface 633.

The first reflecting surface 621 is arranged at a position facing the light emitting element 220 on the front side of the light flux control member 600 with the incident surface 620 interposed therebetween so that the light incident on the incident surface 620 is separated from the optical axis LA of the light emitting element 220. Reflect in the lateral direction. In the present embodiment, the first reflecting surface 621 is rotationally symmetric (circularly symmetric) with respect to the optical axis LA of the light emitting element 220, and is configured to face the front side as the distance from the optical axis LA of the light emitting element 220 increases. Has been done. In the present embodiment, the generatrix from the central portion to the outer peripheral portion of the rotational symmetry is a curve whose angle with respect to the optical axis LA increases as the distance from the optical axis LA of the light emitting element 220 increases. The first reflecting surface 621 is a concave surface in a state where the bus is rotated by 360 ° with the central axis CA of the incident surface 620 as a rotation axis. In the present embodiment, the first reflective surface 621 does not have a plurality of ridges arranged so as to connect the central portion thereof and the outer edge thereof.

In the present embodiment, the incident surface 620 and the first reflecting surface 621 have the light emitted from the center of the light emitting element 220 incident on the incident surface 620, reflected by the first reflecting surface 621, and then reflected by the emitting unit 630. It is configured to reach the first exit surface 633.

The emission unit 630 emits light incident on by the plurality of incident units 610 while guiding the light. In the present embodiment, assuming that the four incident units 610 are arranged at each corner of the virtual quadrangle, the luminous flux control member 600 is arranged along each side at a position corresponding to the four sides of the virtual quadrangle. It has four emission units 630 arranged and one emission unit 630 arranged so as to be surrounded by a virtual quadrangle. Each emission unit 630 is arranged behind the luminous flux control member 600 and has a second emission surface 632 that reflects light from the incident unit 610. Further, the emission unit 630 is arranged on the front side of the light flux control member 600 so as to face the second emission surface 632, and the first emission surface that reflects a part of the light from the incident unit 610 and emits the other part. It has a 633 and an emission promoting unit 340 for promoting the light traveling between the second emission surface 632 and the first emission surface 633 to be emitted from the first emission surface 633.

In this embodiment, the second exit surface 632 is a flat surface (see FIG. 15B). Further, the four first exit surfaces 633 arranged at positions corresponding to the four sides of the virtual quadrangle have a curvature in the direction along the side of the virtual quadrangle and have a curvature in the direction perpendicular to this side. It is a concave surface that does not (see FIG. 15C). On the other hand, the first exit surface 633 arranged so as to be surrounded by the virtual quadrangle is a concave surface formed by a part of the upper bottom and the side surface of the truncated cone arranged upside down (FIGS. 15A and 15C). , See FIG. 16B).

As described above, the plurality of incident units 610 are arranged in a grid pattern corresponding to the arrangement of the light emitting elements 220. The emission promotion unit 340 in the emission unit 630 arranged between the two incident units 610 adjacent to each other in the diagonal direction of the lattice is a concave surface (see FIG. 16B). Further, the emission promoting portion 340 in the emission unit 630 arranged between two incident units 610 adjacent to each other in the side direction of the lattice is a concave surface or a groove. In the present embodiment, the emission promoting portion in the emission unit 630 arranged between two incident units 610 adjacent to each other in the side direction of the lattice is a concave surface.

Further, in the present embodiment, the outer edge on the front side of the luminous flux control member 300 is R-chamfered (see FIG. 10B).

(Light distribution)
Also in the luminous flux control member 600 according to the present embodiment, the light emitted from the light emitting element 220 is incident on the luminous flux control member 600 at the incident surface 620. A part of the light incident on the incident surface 620 is directly directed to the emitting unit 630, and the other part is reflected by the first reflecting surface 621 and directed to the emitting unit 630. The light that has reached the emission unit 630 is repeatedly reflected between the second emission surface 632 and the first emission surface 633, and is guided through the emission unit 630. At this time, a part of the light that has reached the first emission surface 633 is emitted from the first emission surface 633 without being reflected.

In this way, the light that has reached the emission unit 630 travels between the second emission surface 632 and the first emission surface 633 of the emission unit 630, and is gradually emitted from the first emission surface 633. Here, the emission unit 630 has the above-mentioned emission promotion unit. As a result, the farther away from the incident unit 610, the easier it is for the light traveling between the second emission surface 632 and the first emission surface 633 to be emitted from the first emission surface 633.

(Illuminance distribution)
FIG. 17A shows the illuminance distribution of the surface light source device 100 when the luminous flux control member 600 according to the present embodiment is used. FIG. 17B shows the illuminance distribution of the surface light source device when the luminous flux control member 600 is not arranged (only the light emitting element 220) for comparison. FIG. 17C shows the illuminance distribution of the surface light source device when a transparent resin flat plate having substantially the same size is arranged instead of the luminous flux control member 600 for comparison. Here, the illuminance distribution on the light diffusing plate 120 when the four light emitting elements 220 included in one light emitting device are turned on in the surface light source device is shown. In these figures, the lower graph shows the lateral illuminance distribution between the upper two light emitting elements 220 and the lower two light emitting elements 220, and the right graph shows the two right light emitting elements. The illuminance distribution in the vertical direction passing through the light emitting center of the element 220 is shown.

From these results, it can be seen that the luminous flux control member 600 according to the present embodiment spreads the light emitted from each light emitting element 220 and illuminates the region corresponding to each light emitting element 220 substantially uniformly. On the other hand, it can also be seen that the luminous flux control member 600 according to the present embodiment reaches the region corresponding to the light emitting element 220 without excessively mixing the light from each light emitting element 220.

(effect)
In the luminous flux control member 600 according to the second embodiment, in addition to the effect of the luminous flux control member 300 according to the first embodiment, it is difficult for light to escape directly above the light emitting element 220, and it is easier for light to escape between the light emitting elements 220. It has the effect of.

[Embodiment 3]
The luminous flux control member 700 according to the third embodiment is different from the luminous flux control member 300 according to the first embodiment in that the emission promotion unit 340 has a light beam direction changing unit 350. Further, the luminous flux control member 700 according to the third embodiment is different from the luminous flux control member 300 according to the first embodiment in that the emission promotion unit 340 may have a third emission surface 361 and a reincident surface 362. Therefore, in the third embodiment, only the configuration of the emission promotion unit 340 will be described. Further, in the luminous flux control member 700 according to the third embodiment, the same components as those of the luminous flux control member 300 according to the first embodiment are designated by the same reference numerals and the description thereof will be omitted.

(Structure of luminous flux control member)
18A to 19D show the luminous flux control member 700 according to the third embodiment. 18A is a plan view of the luminous flux control member 700 according to the third embodiment, and FIG. 18B is a bottom view of the luminous flux control member 700 according to the third embodiment. 19A is a cross-sectional view taken along the line AA of FIGS. 18A and 18B, FIG. 19B is a cross-sectional view taken along the line BB of FIGS. 18A and 18B, and FIG. 19D is a side view, and FIG. 19E is a cross-sectional view taken along the line EE of FIGS. 18A and 18B.

As shown in FIGS. 18A and 18B, in the present embodiment, the emission promoting unit 340 of the luminous flux control member 700 has a light beam direction changing unit 350 arranged on the back side of the luminous flux control member 700.

As shown in FIG. 18B, the ray direction changing unit 350 has an inclined surface 351 extending along the side direction between two incident units 310 adjacent to each other in the side direction of the grid. Further, in the present embodiment, as shown in FIGS. 19A, B, and C, the light beam direction changing portion 350 is an inner surface of a recess arranged on the back side of the luminous flux control member 700. The light ray direction changing portion 350 may be arranged between two incident units 310 adjacent to each other in the diagonal direction of the grid.

The inclined surface 351 of the light ray direction changing portion 350 changes the direction of the light passing through the emission promoting portion 340. More specifically, the inclined surface 351 reflects light traveling in the side direction of the light flux control member 700 in a direction away from the side when the light flux control member 700 is viewed in a plan view. 20A and 20B are diagrams for explaining how the direction of the light ray is changed by the inclined surface 351 of the light ray direction changing portion 350. FIG. 20A shows the case where the emission promoting unit 340 does not have the light ray direction changing unit 350 for comparison, and FIG. 20B shows the case where the emission promoting unit 340 has the light ray direction changing unit 350. 20A and 20B show the emission promotion unit 340 when the light flux control member 700 is viewed in a plan view, the broken line in FIG. 20B shows the light ray direction changing unit 350 arranged on the back side of the light flux control member 300, and FIG. It is a figure which shows schematic the sectional view along the line CC of FIG. 20B.

Here, as shown in FIG. 20B, the ridge line 352 formed by the two inclined surfaces 351 of the light beam direction changing portion 350 is closer to the center side of the light flux control member 700 than the line connecting the centers of the two incident units 310. Here is an example. Further, as shown in FIG. 20C, the light beam direction changing unit 350 has an inclined surface 351 that inclines so that the distance from the substrate increases from the center side of the light flux control member 700 toward the outside, and the light flux control member 700. It has an inclined surface 351 that is inclined so that the distance from the substrate becomes closer from the inside to the outside. The ridgeline 352 is formed by the tops of the two inclined surfaces 351.

As shown in FIG. 20A, when the emission promoting unit 340 does not have the light beam direction changing unit 350, the light traveling through the emission promoting unit 340 is directed toward the side of the light flux control member 700 between the two incident units 310. Proceed almost linearly along. On the other hand, as shown in FIG. 20B, when the emission promoting unit 340 has the light ray direction changing unit 350, the light traveling through the emission promoting unit 340 hits the inclined surface 351 and is directed to the outside or the center side of the light flux control member 700. Is reflected. In FIG. 20B, the light is reflected toward the outside of the luminous flux control member 700.

The shape of the inclined surface 351 of the light ray direction changing portion 350 may be appropriately designed according to how much light is desired to be reflected in which direction. For example, when the position of the ridge line 352 is moved to the center side of the light flux control member 700, the amount of light directed from the light beam direction changing unit 350 to the outside of the light flux control member 700 increases, and the position of the ridge line 352 is set to the position of the light flux control member 700. When it is moved to the outside, the amount of light directed from the light beam direction changing unit 350 toward the center side of the luminous flux control member 700 increases.

21A to 21F show a modification of the light ray direction changing portion 350.

FIG. 21A shows an example in which the ridge line 352 is outside the example of FIG. 20B and is in the center of the ray direction changing portion 350. 21B is a cross-sectional view taken along the line BB of FIG. 21A. In this ray direction changing portion 350, since the ridge line 352 is at the center of the ray direction changing portion 350, the cross section of the ray direction changing portion 350 is an isosceles triangle having two inclined surfaces 351 having the same length. The light beam direction changing unit 350 can increase the amount of light toward the center side of the light flux control member 700 as compared with the light ray direction changing unit 350 of FIG. 20B.

FIG. 21C shows an example in which the ridge line 352 is further outside from the example of FIG. 20A and outside the center of the ray direction changing portion 350. Note that FIG. 21D is a cross-sectional view taken along the line DD of FIG. 21C. The light beam direction changing unit 350 can increase the amount of light toward the center side of the light flux control member 700 more than the light ray direction changing unit 350 of FIG. 21A.

21A to 21D show an example in which the ridgeline 352 of the light ray direction changing portion 350 is a straight line, but the ridgeline 352 is not limited to a straight line and may be appropriately designed according to the direction in which light is desired to be reflected. For example, FIGS. 21E and 21F show an example in which the ridge line 352 is a curve. 21F is a cross-sectional view taken along the line FF of FIG. 21E.

Further, as shown in FIG. 18A, in the luminous flux control member 700 according to the third embodiment, the emission promotion unit 340 in the emission unit 330 arranged between the two incident units 310 adjacent to each other in the side direction of the lattice is , Has a third exit surface 361 and a reincident surface 362 arranged on the front side of the luminous flux control member 700. Hereinafter, the third exit surface 361 and the reincident surface 362 will be described with reference to FIG. 22, which is a cross-sectional view taken along the line BB of FIG. 18A.

As shown in FIG. 22, the third emission surface 361 is arranged so as to face the first reflection surface 321 on the front side of the luminous flux control member 700, and is emitted from the light emitting element 220 as shown by a solid arrow. 1 Light reflected laterally by the reflecting surface 321 is emitted to the outside of the luminous flux control member 700. Further, as shown in FIG. 22, the reincident surface 362 is arranged on the front side of the luminous flux control member 700 with respect to the first reflection surface 321 and farther than the third emission surface 361, and is shown by a solid line. 3 The light emitted from the emission surface 361 is incident again into the luminous flux control member 700 toward the light beam direction changing unit 350.

The broken line arrow in FIG. 22 shows an example of the traveling direction of the light ray when the third exit surface 361 and the reincident surface 362 are not present. As shown by the broken arrow in FIG. 22, in the absence of the third exit surface 361 and the reincident surface 362, the light reflected by the first reflection surface 321 may travel substantially parallel to the substrate, and the light ray direction changing portion. It does not hit 350, and the traveling direction of light is hard to change. On the other hand, as described above, when the third exit surface 361 and the reincident surface 362 are present, the direction of the light reflected by the first reflection surface 321 is changed, and the light ray direction changing portion 350 is easily hit.

Further, in the luminous flux control member 700 according to the third embodiment, as shown in FIG. 19E, the emission promotion unit 340 arranged diagonally of the luminous flux control member 700 is the first reflection on the front side of the luminous flux control member 700. It has a third exit surface 361 arranged so as to face the surface 321. The third emission surface 361 emits the light reflected by the first reflection surface 321 to the outside of the luminous flux control member 700. As a result, the brightness of the central portion (the portion surrounded by the four incident units) of the luminous flux control member 700 is improved.

(Illuminance distribution)
FIG. 23A shows the illuminance distribution of the surface light source device 100 when a light flux control member having no light beam direction changing unit 350 is used, and FIG. 23B shows a light flux control member having a light beam direction changing unit 350 shown in FIG. The illuminance distribution of the surface light source device 100 when 700 is used is shown. Here, the illuminance distribution on the light diffusing plate 120 when the four light emitting elements 220 included in one light emitting device are turned on in the surface light source device is shown. In these figures, the lower graph shows the lateral illuminance distribution between the upper two light emitting elements 220 and the lower two light emitting elements 220, and the right graph shows the two right light emitting elements. The illuminance distribution in the vertical direction passing through the light emitting center of the element 220 is shown.

From the comparison of the lower graphs of FIGS. 23A and 23B, it can be seen that when the light flux control member 700 has the light beam direction changing portion 350, the light spreads outward from the center of the light flux control member 700.

(effect)
The luminous flux control member 700 according to the present embodiment has an effect that, in addition to the effect of the luminous flux control member 300 according to the first embodiment, the direction of the light traveling through the emission promoting unit 340 can be changed to further improve the luminance unevenness. ..

[Embodiment 4]
The light flux control member 800 according to the fourth embodiment is different from the light flux control member 700 according to the third embodiment in that it has a light beam direction changing portion 350 arranged between the incident units 310 adjacent to each other in the diagonal direction of the grid. .. Therefore, in the fourth embodiment, these configurations will be mainly described. Further, in the luminous flux control member 800 according to the fourth embodiment, the same components as those of the luminous flux control member 700 according to the third embodiment are designated by the same reference numerals and the description thereof will be omitted.

(Structure of luminous flux control member)
FIGS. 24A to 24F show the luminous flux control member 800 according to the fourth embodiment. 24A shows a plan view of the luminous flux control member 800, FIG. 24B shows a bottom view, FIG. 24C shows a perspective view, FIG. 24D shows a side view, and FIG. 24E shows a cross section taken along the line EE of FIG. 24A. FIG. 24F shows a cross-sectional view taken along the line FF of FIG. 24A.

As shown in FIGS. 24B, C, E, and F, the luminous flux control member 800 has a light beam direction changing portion 350 having an inclined surface 351 on the back side of the luminous flux control member 800. In the case of the present embodiment, the light beam direction changing unit 350 is arranged in an annular shape around the center of the light flux control member 800. Along with this, the inclined surface 351 also extends in an annular shape, and the ridge line 352 also extends in an annular shape (see FIG. 24B).

Further, as shown in FIGS. 24E and 24F, the luminous flux control member 800 has a third exit surface 361 and a re-incident surface 362 arranged between two incident units 310 adjacent to each other in the diagonal direction of the grid. .. The third exit surface 361 emits the light reflected by the first reflection surface 321 to the outside of the luminous flux control member 800, and the re-incident surface 362 re-incidents the emitted light.

Further, as shown in FIGS. 24A to 24F, the luminous flux control member 800 has a leg portion 370 arranged on the back side thereof. The position and number of legs 370 are not particularly limited.

Further, as shown in FIGS. 24A to 24F, the luminous flux control member 800 has a gate portion 280 arranged on the back side thereof. The position and number of gate portions 380 are not particularly limited.

(Illuminance distribution)
FIG. 25 shows the illuminance distribution of the surface light source device 100 when the luminous flux control member 800 is used. Here, the illuminance distribution on the light diffusing plate 120 when the four light emitting elements 220 included in one light emitting device are turned on in the surface light source device is shown. In this figure, the lower graph shows the lateral illuminance distribution between the upper two light emitting elements 220 and the lower two light emitting elements 220, and the right graph shows the right two light emitting elements. The illuminance distribution in the vertical direction passing through the emission center of 220 is shown.

As shown in FIG. 25, since the luminous flux control member 800 has a large number of emission promoting portions 340 on the back side, it can be seen that the brightness of the central portion of the luminous flux control member 800 is improved.

(effect)
The luminous flux control member 800 according to the present embodiment has an effect that the luminance of the central portion can be improved and the luminance unevenness can be further improved, in addition to the effect of the luminous flux control member 300 according to the third embodiment.

[Embodiment 5]
In the light flux control member 900 according to the fifth embodiment, the shape of the light beam direction changing unit 350 is different from the light flux control member 800 according to the fourth embodiment, and the light beam direction change is arranged on the back side more than the light flux control member 800. It has a unit 350. Therefore, in the fifth embodiment, these configurations will be mainly described. Further, in the luminous flux control member 900 according to the fifth embodiment, the same members as those in the fourth embodiment are designated by the same reference numerals, and the description thereof will be omitted.

(Structure of luminous flux control member)
26A to 26F show the luminous flux control member 900 according to the fifth embodiment. 26A shows a plan view of the luminous flux control member 900, FIG. 26B shows a bottom view, FIG. 26C shows a perspective view, FIG. 26D shows a side view, and FIG. 26E shows a cross section taken along the line EE of FIG. 26A. FIG. 26F shows a cross-sectional view taken along the line FF of FIG. 26A.

As shown in FIGS. 26B and 26C, the light beam direction changing portion 350 of the luminous flux control member 900 has four inclined surfaces 351 (see FIG. 26B). The two inclined surfaces 351 face each other in the direction outward from the center of the light flux control member 900, and the remaining two inclined surfaces 351 face each other in the direction along the sides of the light flux control member 900.

Further, the luminous flux control member 900 has a light beam direction changing portion 350 having an inclined surface 351 around the center on the back side. In the present embodiment, the inclined surface 351 extends circularly around the center of the luminous flux control member 900. Further, in the present embodiment, the light ray direction changing portion 350 does not have a ridgeline but has an apex.

(Illuminance distribution)
FIG. 27 shows the illuminance distribution of the surface light source device 100 when the luminous flux control member 900 is used. Here, the illuminance distribution on the light diffusing plate 120 when the four light emitting elements 220 included in one light emitting device are turned on in the surface light source device is shown. In this figure, the lower graph shows the lateral illuminance distribution between the upper two light emitting elements 220 and the lower two light emitting elements 220, and the right graph shows the right two light emitting elements. The illuminance distribution in the vertical direction passing through the emission center of 220 is shown.

As shown in FIG. 27, since the luminous flux control member 900 has the inclined surface 351 as described above, it can be seen that the brightness between the two incident units 310 arranged in the side direction is improved.

(effect)
The luminous flux control member 900 according to the present embodiment has an effect that, in addition to the effect of the luminous flux control member 300 according to the fourth embodiment, the brightness between two incident units 310 arranged in the side direction can be improved. Has.

[Mounting method of luminous flux control member]
Next, a method of mounting the luminous flux control member according to the present invention on the substrate 210 will be described below with reference to FIG. 28, using the luminous flux control member 300 as an example.

First, as shown in the upper part of FIG. 28, the center α of the plurality of light emitting elements 220 arranged on the substrate 210 is determined. Specifically, the centers α of the four light emitting elements 220 arranged in a grid pattern are determined. The method for determining the center α is not particularly limited. For example, the intersection of the diagonal lines of a quadrangle whose angle is the center of each of the four light emitting elements 220 may be the center α, or the center of gravity of this quadrangle may be the center α.

The substrate 210 may be marked for mounting. The location of the mark is not particularly limited, but it is preferable to give the mark at a position corresponding to the center α, for example.

Next, as shown in the middle of FIG. 28, the center β of the luminous flux control member 300 is determined. The method for determining the central β is not particularly limited. For example, the intersection of the diagonal lines of a quadrangle whose angle is the center of each of the four incident units 310 (first reflecting surface 321) may be the center β, or the center of gravity of this quadrangle may be the center β.

The luminous flux control member 300 may be marked for mounting. The location of the mark is not particularly limited, but for example, it is preferable to give the mark to a flat surface instead of each reflecting surface or the emission promoting portion.

Finally, the luminous flux control member 300 is mounted on the substrate so that the center α of the plurality of light emitting elements 220 and the center β of the luminous flux control member 300 coincide with each other. By doing so, the luminous flux control member 300 can be efficiently mounted on the substrate 210 in which the plurality of light emitting elements 220 are arranged.

Further, it is possible to recognize the outer edge of the luminous flux control member 300 in a plan view and use it for alignment in the rotation direction.

100-sided light source device 100'display device 102 display member 110 housing 112 bottom plate 114 top plate 120 light diffuser plate 200 light emitting device 210 board 220 light emitting element 300, 400, 500, 600, 700, 800, 900 luminous flux control member 310, 610 Incident unit 320, 620 Incident surface 321, 621 First reflection surface 330, 630 Emission unit 332, 632 Second emission surface 333, 633 First emission surface 340 Emission promotion part 350 Light direction change part 351 Inclined surface 352 Ridge line 361 Third Emitting surface 362 Reincident surface 370 Leg 380 Gate 390 Convex 391 First inclined surface 392 Second inclined surface 393 Convex ridge CA Central axis LA Optical axis

Claims (18)

A luminous flux control member for controlling the light distribution of light emitted from a plurality of light emitting elements arranged on a substrate.
A plurality of incident units for incident light emitted from the plurality of light emitting elements, and
A plurality of emitting units arranged between the plurality of incident units in a direction along the substrate and emitting light incident on the plurality of incident units while guiding the light.
Have,
The plurality of incident units are respectively arranged on the back side of the luminous flux control member, and have an incident surface on which light emitted from the light emitting element is incident.
A first unit that is arranged on the front side of the luminous flux control member at a position facing the light emitting element with the incident surface interposed therebetween, and reflects light incident on the incident surface laterally so as to be away from the optical axis of the light emitting element. Reflective surface and
Have,
Each of the plurality of emission units is arranged on the back side of the luminous flux control member, and has a second emission surface that reflects a part of the light from the incident unit and emits the other part.
A first emission surface which is arranged on the front side of the luminous flux control member so as to face the second emission surface, reflects a part of the light from the incident unit, and emits the other part.
An emission promoting unit arranged on at least one of the first emission surface and the second emission surface and for promoting the emission of light traveling between the first emission surface and the second emission surface. ,
Have,
The emission promoting unit includes a light ray direction changing unit including an inclined surface that changes the traveling direction of the reached light.
Luminous flux control member. The emission promotion unit is
A third emission surface arranged on the front side of the light flux control member so as to face the first reflection surface and for emitting light laterally reflected by the first reflection surface to the outside of the light flux control member. including,
The luminous flux control member according to claim 1. The luminous flux control member is arranged in a grid pattern on a substrate, and the light beam direction changing portion is arranged between two incident units adjacent to each other in the side direction of the grid.
The luminous flux control member according to claim 1 or 2. The luminous flux control member is arranged in a grid pattern on a substrate, and the third emission surface is arranged between two incident units adjacent to each other in the side direction of the grid.
The luminous flux control member according to claim 2. The luminous flux control member according to claim 1, wherein the emission promoting unit includes a portion of the emission unit in which the distance between the second emission surface and the first emission surface becomes smaller as the distance from the incident unit increases. The emission promoting portion is at least one selected from the group consisting of a concave surface, a rough surface, a Fresnel surface, a groove, and a through hole, which are arranged on at least one of the second emission surface and the first emission surface. The luminous flux control member according to claim 1 or 2. The luminous flux control member according to any one of claims 1 to 3, wherein the outer edge on the front side of the luminous flux control member has a chamfered shape. The luminous flux control member according to any one of claims 1 to 4, wherein the light emitted from the center of the light emitting element and incident on the incident surface reaches the first reflecting surface and the first emitting surface. The incident surface and the first reflecting surface are the inner surfaces of the recesses, respectively.
When viewed in a plan view, the area of the opening edge of the recess constituting the first reflecting surface is 0.5 to 2.0 times the area of the opening edge of the recess constituting the incident surface. The luminous flux control member according to any one of claims 1 to 5. The luminous flux control member is arranged in a grid pattern on a substrate, and the emission promoting portion in the emission unit arranged between two adjacent incident units in the diagonal direction of the lattice includes a concave surface. The luminous flux control member according to claim 1. The luminous flux control member is arranged in a grid pattern on a substrate, and the emission promoting portion in the emission unit arranged between two adjacent incident units in the side direction of the lattice includes a concave surface or a groove. , The luminous flux control member according to claim 1 or 8. The emission promotion unit is
A third emission surface arranged on the front side of the light flux control member so as to face the first reflection surface and for emitting light laterally reflected by the first reflection surface to the outside of the light flux control member. When,
On the front side of the luminous flux control member, the light is arranged farther than the third emission surface with respect to the first reflection surface, and the light emitted from the third emission surface is transferred to the light beam direction changing portion in the light flux control member. The re-incident surface to be re-incident toward the surface and
The luminous flux control member according to claim 1. One of claims 1 to 12, wherein the first reflecting surface is rotationally symmetric with respect to the optical axis of the light emitting element and is configured to face the front side as the distance from the optical axis of the light emitting element increases. The light flux control member according to item 1. The luminous flux control member according to claim 13, wherein the first reflecting surface has a plurality of ridges arranged so as to connect a central portion thereof and an outer edge thereof. With multiple light emitting elements arranged on the substrate,
The luminous flux control member according to any one of claims 1 to 14, which is arranged on the plurality of light emitting elements.
A light emitting device. A plurality of light emitting devices according to claim 15,
A light diffusing plate that diffuses and transmits light emitted from the plurality of light emitting devices,
A surface light source device. The plurality of light emitting elements and the plurality of light emitting devices are all arranged in a grid pattern and separated from each other.
The distance between the adjacent light emitting devices is smaller than half of the distance between the centers of the plurality of light emitting elements.
The surface light source device according to claim 16. The surface light source device according to claim 16 or 17.
A display member that is irradiated with light emitted from the surface light source device, and
Has a display device.

Images